Firstly, for the acoustic rating value to be credible, it must have been obtained in an accredited laboratory. At ISP, all of our acoustic testings are carried out and certs are obtained and issued by TÜV SÜD PSB.
TÜV SÜD PSB is accredited under the Singapore Accreditation Council Singapore Laboratory Accreditation (SAC-Singlas) Scheme and its acoustics laboratory is the most comprehensive in Southeast Asia, offering world-class acoustics testing services to meet various international standards ranging from ISO, ASTM, BS, IEC and national requirements.
For our systems, they are tested for the laboratory measurement of airborne sound transmission loss (TL) and the sound insulation rating was computed according to ASTM E413. The results of the tested partition or door system are then denoted by the sound transmission class (STC), which is an integer rating of how well a building partition attenuates airborne sound.
Note: When comparing one acoustic certification to another, direct comparison should be made in accordance with the tested product and testing conditions.